1. Field of the Disclosure
The present disclosure relates to an organic light-emitting display device and a method of manufacturing the same. More particularly, the present disclosure relates to an organic light emitting display device which comprises features to prevent penetration of external impurities, such as oxygen or water, and a method of manufacturing the organic light-emitting display device with these features.
2. Description of the Related Art
Recently, conventional display devices are being replaced with portable, thin flat panel display devices. Electroluminescent display devices have become widely used in flat panel display devices. An electroluminescent display device is a self-emissive display and has a wide viewing angle, high contrast ratio, and high response speed. An organic light-emitting display is one type of electroluminescent display. In an organic light-emitting display device, a light emitting layer is formed of an organic material and is popular because is has improved properties in terms of brightness, driving voltage, response speed, and can realize multiple colors in comparison to an inorganic light-emitting display device.
FIG. 1 is a cross-sectional view of a conventional organic light-emitting display device. Referring to FIG. 1, a display unit 20 is formed on a substrate 10, and an encapsulation substrate 30 is formed above the display unit 20. The substrate 10 and the encapsulation substrate 30 are attached to each other using a sealant 41.
A flat panel display device, particularly an organic light emitting device, may suffer deterioration because of factors, such as deterioration of the light emitting layer. For example, oxygen may contaminate the indium tin oxide (ITO) used in the electrode of the device. Deterioration may also result from a reaction between the light emitting layer and an interface. External contaminants, such as water, oxygen, ultraviolet rays reaching the organic light emitting device from the outside, and the manufacturing conditions of the organic light emitting device, may also contribute to deterioration of the device. Oxygen and water from the outside can especially affect the life span of an organic light emitting device. Thus, the protective features and packaging of the organic light emitting device can be critical.
Referring now to FIG. 1, a conventional organic light-emitting display device is shown. Impurities, such as oxygen or water, may penetrate into the organic light-emitting display device through interfaces between the sealant 41 and the encapsulation substrate 30. The display unit 20 may thus result from these impurities.
Conventionally, a filling film (not shown) or a filler (not shown) between the substrate 10 and the encapsulation substrate 30 have been employed. A dam (not shown) has also been provided between the sealant 41 and the filling film or the filler in other conventional devices.
However, a filler or filling film between the substrate 10 and the encapsulation substrate 30 may not provide adequate protection. For example, when the adhesive strength of the filler is too great, the filler does not completely spread between the substrate 10 and the encapsulation substrate 30 and unoccupied areas or gaps may remain in the device. These gaps may allow for contaminants in the device and allow for increased problems with exfoliation. For example, when an empty space or gap remains, initially a spot defect may occur due to a difference in color coordinates or luminance, when that empty space is illuminated. These empty spaces may also occur due to outgassing from the organic material or filler when reliability testing is performed. During such testing, pressure may be exerted on and around the empty space and also cause an exfoliation defect to occur.